This invention relates to a fibrous pen for recording instruments and the like wherein the tip of the fibrous or lamella writing nib extending from the end of the writing tube may be permanently positioned by bending the writing tube.
Various fibrous pen constructions for use with recording instruments and the like have been known in the art. In one prior art construction a metallic writing tube having a fibrous or lamella writing nib projecting from the free end thereof extends from a plastic ink supply container. This fibrous pen construction is produced by injection molding the plastic ink supply container in a mold in which the metallic writing tube has been previously positioned whereby the writing tube is permanently attached to the plastic ink supply container. This requires complex injection molding apparatus, and also anchoring means must be provided to secure one end of the metallic writing tube in the plastic ink supply container.
In another embodiment, one end of a metallic writing tube may be secured to a plastic ink supply container by press-fitting or bonding the end of the metallic writing tube in a bore of a previously formed plastic ink supply container. However, this has the disadvantage that frequently torsion of the metallic writing tube with respect to the plastic ink supply container and leakage around the seal between the metallic writing tube and the plastic ink supply container cannot always be prevented.
Frequently, in recording instrument constructions, which include a plurality of writing tubes, it is not possible for each writing tube to extend in a straight line from the plastic ink supply container to a predetermined writing position due to the fact that several of the fibrous pens must be positioned in a relatively narrow space and the distance between writing nibs of adjacent fibrous pens must be relatively short. Thus, it is often absolutely necessary for the writing tube to have a configuration other than a straight line.
Fibrous pens have been known in the art which comprise an ink supply container and a writing tube which are made as a single unit by injection molding of plastic material. The plastic writing tube is subsequently deformed thermally to position the writing nib at a desired location. The disadvantage of this construction has been that in the course of time during use, and particularly in the presence of increased ambient temperatures, the configuration of the plastic writing tube changes due to the fact that the plastic writing tube tends to recover its initial straight configuration. Consequently, the writing nib moves from the desired or predetermined location resulting in the recording of data which is unreliable.
An object of the present invention is to provide a fibrous pen construction in which the writing tube is permanently secured to the plastic ink supply container such that the problems associated with torsion and leakage are avoided and in which the configuration of the writing tube remains fixed after deformation or bending of the writing tube to position the tip of the writing nib at a desired or predetermined location.